int main()
{
    int n,m;
    char s[10];
    for(n=6;; n+=10)
    {
        sprintf(s,"%d%d",n%10,n/10);//s="612345";
        sscanf(s,"%d",&m);//m=612345
        if(m==4*n)
        {
            printf("%d*4=%d\n",n,m);
            break;
        }
    }
}
